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https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf.git
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36d83c249e
When neither sysenter32 nor syscall32 is available (on either FRED-capable 64-bit hardware or old 32-bit hardware), there is no reason to do a bunch of stack shuffling in __kernel_vsyscall. Unfortunately, just overwriting the initial "push" instructions will mess up the CFI annotations, so suffer the 3-byte NOP if not applicable. Similarly, inline the int $0x80 when doing inline system calls in the vdso instead of calling __kernel_vsyscall. Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://patch.msgid.link/20251216212606.1325678-11-hpa@zytor.com
106 lines
3.3 KiB
C
106 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Macros for issuing an inline system call from the vDSO.
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*/
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#ifndef X86_ASM_VDSO_SYS_CALL_H
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#define X86_ASM_VDSO_SYS_CALL_H
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#include <linux/compiler.h>
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#include <asm/cpufeatures.h>
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#include <asm/alternative.h>
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#ifdef CONFIG_X86_64
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# define __sys_instr "syscall"
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# define __sys_clobber "rcx", "r11", "memory"
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# define __sys_nr(x,y) __NR_ ## x
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# define __sys_reg1 "rdi"
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# define __sys_reg2 "rsi"
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# define __sys_reg3 "rdx"
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# define __sys_reg4 "r10"
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# define __sys_reg5 "r8"
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#else
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# define __sys_instr ALTERNATIVE("ds;ds;ds;int $0x80", \
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"call __kernel_vsyscall", \
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X86_FEATURE_SYSFAST32)
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# define __sys_clobber "memory"
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# define __sys_nr(x,y) __NR_ ## x ## y
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# define __sys_reg1 "ebx"
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# define __sys_reg2 "ecx"
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# define __sys_reg3 "edx"
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# define __sys_reg4 "esi"
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# define __sys_reg5 "edi"
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#endif
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/*
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* Example usage:
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*
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* result = VDSO_SYSCALL3(foo,64,x,y,z);
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*
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* ... calls foo(x,y,z) on 64 bits, and foo64(x,y,z) on 32 bits.
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*
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* VDSO_SYSCALL6() is currently missing, because it would require
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* special handling for %ebp on 32 bits when the vdso is compiled with
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* frame pointers enabled (the default on 32 bits.) Add it as a special
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* case when and if it becomes necessary.
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*/
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#define _VDSO_SYSCALL(name,suf32,...) \
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({ \
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long _sys_num_ret = __sys_nr(name,suf32); \
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asm_inline volatile( \
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__sys_instr \
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: "+a" (_sys_num_ret) \
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: __VA_ARGS__ \
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: __sys_clobber); \
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_sys_num_ret; \
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})
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#define VDSO_SYSCALL0(name,suf32) \
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_VDSO_SYSCALL(name,suf32)
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#define VDSO_SYSCALL1(name,suf32,a1) \
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({ \
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register long _sys_arg1 asm(__sys_reg1) = (long)(a1); \
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_VDSO_SYSCALL(name,suf32, \
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"r" (_sys_arg1)); \
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})
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#define VDSO_SYSCALL2(name,suf32,a1,a2) \
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({ \
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register long _sys_arg1 asm(__sys_reg1) = (long)(a1); \
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register long _sys_arg2 asm(__sys_reg2) = (long)(a2); \
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_VDSO_SYSCALL(name,suf32, \
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"r" (_sys_arg1), "r" (_sys_arg2)); \
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})
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#define VDSO_SYSCALL3(name,suf32,a1,a2,a3) \
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({ \
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register long _sys_arg1 asm(__sys_reg1) = (long)(a1); \
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register long _sys_arg2 asm(__sys_reg2) = (long)(a2); \
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register long _sys_arg3 asm(__sys_reg3) = (long)(a3); \
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_VDSO_SYSCALL(name,suf32, \
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"r" (_sys_arg1), "r" (_sys_arg2), \
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"r" (_sys_arg3)); \
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})
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#define VDSO_SYSCALL4(name,suf32,a1,a2,a3,a4) \
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({ \
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register long _sys_arg1 asm(__sys_reg1) = (long)(a1); \
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register long _sys_arg2 asm(__sys_reg2) = (long)(a2); \
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register long _sys_arg3 asm(__sys_reg3) = (long)(a3); \
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register long _sys_arg4 asm(__sys_reg4) = (long)(a4); \
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_VDSO_SYSCALL(name,suf32, \
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"r" (_sys_arg1), "r" (_sys_arg2), \
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"r" (_sys_arg3), "r" (_sys_arg4)); \
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})
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#define VDSO_SYSCALL5(name,suf32,a1,a2,a3,a4,a5) \
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({ \
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register long _sys_arg1 asm(__sys_reg1) = (long)(a1); \
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register long _sys_arg2 asm(__sys_reg2) = (long)(a2); \
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register long _sys_arg3 asm(__sys_reg3) = (long)(a3); \
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register long _sys_arg4 asm(__sys_reg4) = (long)(a4); \
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register long _sys_arg5 asm(__sys_reg5) = (long)(a5); \
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_VDSO_SYSCALL(name,suf32, \
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"r" (_sys_arg1), "r" (_sys_arg2), \
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"r" (_sys_arg3), "r" (_sys_arg4), \
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"r" (_sys_arg5)); \
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})
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#endif /* X86_VDSO_SYS_CALL_H */
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